A connecting rod, also called a conrod, provides a link between a piston and an engine crankshaft in an internal combustion engine. The connecting rod of an engine is subject to tremendous stress from an associated piston during the combustion cycle as well as stresses from a drive train when an engine absorbs energy from overdriven wheels. These stresses can cause failure of a connecting rod, which causes catastrophic failure of an associated engine.
Connecting rods are attached to a piston at one end and to a crankshaft at an opposite end. At the crankshaft end, the connecting rod typically has a cap portion that is attached to the main body of the connecting rod by a plurality of bolts. The stress transmitted through the connecting rod alternatively causes stretching and relaxation of the bolts holding the cap portion to the main body, which can cause a loosening of the clamp load on the crankshaft, leading to failure of the connecting rod. Improving the consistency of clamp load, particularly the loading on contact surfaces between the cap portion and the main body portion, can improve the life of a connecting rod, which can then increase the life and reliability of an associated internal combustion engine.